Conventional processes for forming bricks include a process wherein extruded clay slugs are coated with a layer of sand, deposited into mold boxes, then dried and heated until hardened. This process is a mechanical imitation of an ancient manner in which bricks were hand made, and is used to create a brick with a specific appearance.
In the process described above, wet clay passes through a conical funnel, which uses an auger to move the clay through what is, in most cases, a vertical extruder. Clay is ejected from the funnel at a predetermined rate, and a wire is used to cut a predetermined amount of the clay from the discharge outlet of the funnel. The portion of clay that is discharged from the funnel and cut by the wire, called a slug, is coated with a layer of sand, then deposited into a mold box, which is generally in the shape of the desired brick. Thereafter, the clay is removed from the mold box, dried, and heated to a finished state.
Because of the demand for bricks of varying colors and textures, a common technique is to color the sand that is used to coat the clay slug that is ejected from the extruder in order to produce bricks having different colors. However, not only are the possible color combinations limited with the above-described method, in some instances, the sand does not adhere to the surface of the brick, and thus the color of the brick is not effectively altered. This makes the process very unreliable and the appearance of the resulting brick non-uniform.
Further, because the process of changing from making a brick having one color to a brick having a different color is labor intensive, bricks having a single color have to be mass produced in very large quantities for the operation to be cost effective. For example, one unit containing a large number of bricks of a single color is first produced, then another unit containing a large number of bricks of one color that is different from the previous runs are produced separately. Thus, if it is desired to have a single unit of bricks containing bricks of several different colors, it is necessary to resort the bricks to combine the different colors. Alternatively, several pallets, with each pallet containing bricks of a single color, could be delivered to a job site for resorting by hand during the installation process. However, resorting by hand greatly slows the installation process.
Further, the method of imparting a color change to bricks with the method described above creates problems when it becomes necessary to repeat or reproduce a previously produced brick having a specific appearance. In particular, because of the unreliability of the sand adhering to the brick, the chances of reproducing a brick having a color matching that of a previously produced brick are small.
Other methods of coloring the brick have included the addition of colorants to the outer portion of the body of the bricks, and submerging columns of clay, or bricks, in a liquid base dye. However, these methods are expensive, and color reproducibility is very difficult. Moreover, these methods are also very limited in the amount of color variations that can be achieved, and again, it becomes very difficult to manufacture a combination of different colors simultaneously.
Further still, the methods discussed above relating to the conventional ways in which a color is added to a brick require additional and wholly separate processes to be performed on the clay, apart from the structural fabrication of the brick. This translates to additional cost and expense for new work stations on the production line and in additional steps in an assembly line manufacturing setting, where most brick manufacturing is generally performed, thus increasing the cost of manufacturing.